diff --git a/api/main.go b/api/main.go
index edfc8a8..06cbfcd 100644
--- a/api/main.go
+++ b/api/main.go
@@ -80,7 +80,6 @@ func New() *WebAPI {
 			ctx.SetStatusCode(404)
 			_, _ = fmt.Fprintf(ctx, "Not found")
 		}
-
 	}
 
 	return api
diff --git a/api/task.go b/api/task.go
index b31f201..d7fefab 100644
--- a/api/task.go
+++ b/api/task.go
@@ -8,7 +8,6 @@ import (
 	"errors"
 	"github.com/Sirupsen/logrus"
 	"github.com/dchest/siphash"
-	"github.com/google/uuid"
 	"src/task_tracker/storage"
 	"strconv"
 )
@@ -114,9 +113,9 @@ func (api *WebAPI) TaskGetFromProject(r *Request) {
 		return
 	}
 
-	project, err := strconv.Atoi(r.Ctx.UserValue("project").(string))
+	project, err := strconv.ParseInt(r.Ctx.UserValue("project").(string), 10, 64)
 	handleErr(err, r)
-	task := api.Database.GetTaskFromProject(worker, int64(project))
+	task := api.Database.GetTaskFromProject(worker, project)
 
 	if task == nil {
 
@@ -159,7 +158,7 @@ func (api WebAPI) validateSignature(r *Request) (*storage.Worker, error) {
 	widStr := string(r.Ctx.Request.Header.Peek("X-Worker-Id"))
 	signature := r.Ctx.Request.Header.Peek("X-Signature")
 
-	wid, err := uuid.Parse(widStr)
+	wid, err := strconv.ParseInt(widStr, 10, 64)
 	if err != nil {
 		logrus.WithError(err).WithFields(logrus.Fields{
 			"wid": widStr,
@@ -219,7 +218,7 @@ func (api *WebAPI) TaskRelease(r *Request) {
 	var req ReleaseTaskRequest
 	if r.GetJson(&req) {
 
-		res := api.Database.ReleaseTask(req.TaskId, &worker.Id, req.Success)
+		res := api.Database.ReleaseTask(req.TaskId, worker.Id, req.Success)
 
 		response := ReleaseTaskResponse{
 			Ok: res,
diff --git a/api/worker.go b/api/worker.go
index 8c5712f..90b10c0 100644
--- a/api/worker.go
+++ b/api/worker.go
@@ -2,9 +2,9 @@ package api
 
 import (
 	"github.com/Sirupsen/logrus"
-	"github.com/google/uuid"
 	"math/rand"
 	"src/task_tracker/storage"
+	"strconv"
 	"time"
 )
 
@@ -34,8 +34,8 @@ type GetWorkerResponse struct {
 }
 
 type WorkerAccessRequest struct {
-	WorkerId  *uuid.UUID `json:"worker_id"`
-	ProjectId int64      `json:"project_id"`
+	WorkerId  int64 `json:"worker_id"`
+	ProjectId int64 `json:"project_id"`
 }
 
 type WorkerAccessResponse struct {
@@ -79,17 +79,27 @@ func (api *WebAPI) WorkerCreate(r *Request) {
 
 func (api *WebAPI) WorkerGet(r *Request) {
 
-	id, err := uuid.Parse(r.Ctx.UserValue("id").(string))
+	id, err := strconv.ParseInt(r.Ctx.UserValue("id").(string), 10, 64)
 	if err != nil {
-		logrus.WithFields(logrus.Fields{
+		logrus.WithError(err).WithFields(logrus.Fields{
 			"id": id,
-		}).Warn("Invalid UUID")
+		}).Warn("Invalid worker id")
 
 		r.Json(GetWorkerResponse{
 			Ok:      false,
 			Message: err.Error(),
 		}, 400)
 		return
+	} else if id <= 0 {
+		logrus.WithFields(logrus.Fields{
+			"id": id,
+		}).Warn("Invalid worker id")
+
+		r.Json(GetWorkerResponse{
+			Ok:      false,
+			Message: "Invalid worker id",
+		}, 400)
+		return
 	}
 
 	worker := api.Database.GetWorker(id)
@@ -188,7 +198,6 @@ func (api *WebAPI) workerCreate(request *CreateWorkerRequest, identity *storage.
 	}
 
 	worker := storage.Worker{
-		Id:       uuid.New(),
 		Created:  time.Now().Unix(),
 		Identity: identity,
 		Secret:   makeSecret(),
diff --git a/schema.sql b/schema.sql
index ff200ef..8770170 100755
--- a/schema.sql
+++ b/schema.sql
@@ -25,7 +25,7 @@ CREATE TABLE worker_identity
 
 CREATE TABLE worker
 (
-  id       TEXT PRIMARY KEY,
+  id       SERIAL PRIMARY KEY,
   alias    TEXT,
   created  INTEGER,
   identity INTEGER REFERENCES worker_identity (id),
@@ -46,7 +46,7 @@ CREATE TABLE project
 
 CREATE TABLE worker_has_access_to_project
 (
-  worker  TEXT REFERENCES worker (id),
+  worker  INTEGER REFERENCES worker (id),
   project INTEGER REFERENCES project (id),
   primary key (worker, project)
 );
@@ -56,7 +56,7 @@ CREATE TABLE task
   id              SERIAL PRIMARY KEY,
   priority        INTEGER DEFAULT 0,
   project         INTEGER REFERENCES project (id),
-  assignee        TEXT REFERENCES worker (id),
+  assignee        INTEGER REFERENCES worker (id),
   retries         INTEGER DEFAULT 0,
   max_retries     INTEGER,
   status          Status  DEFAULT 'new',
diff --git a/storage/task.go b/storage/task.go
index 785bcde..2851b3f 100644
--- a/storage/task.go
+++ b/storage/task.go
@@ -4,20 +4,19 @@ import (
 	"database/sql"
 	"fmt"
 	"github.com/Sirupsen/logrus"
-	"github.com/google/uuid"
 )
 
 type Task struct {
-	Id            int64     `json:"id"`
-	Priority      int64     `json:"priority"`
-	Project       *Project  `json:"project"`
-	Assignee      uuid.UUID `json:"assignee"`
-	Retries       int64     `json:"retries"`
-	MaxRetries    int64     `json:"max_retries"`
-	Status        string    `json:"status"`
-	Recipe        string    `json:"recipe"`
-	MaxAssignTime int64     `json:"max_assign_time"`
-	AssignTime    int64     `json:"assign_time"`
+	Id            int64    `json:"id"`
+	Priority      int64    `json:"priority"`
+	Project       *Project `json:"project"`
+	Assignee      int64    `json:"assignee"`
+	Retries       int64    `json:"retries"`
+	MaxRetries    int64    `json:"max_retries"`
+	Status        string   `json:"status"`
+	Recipe        string   `json:"recipe"`
+	MaxAssignTime int64    `json:"max_assign_time"`
+	AssignTime    int64    `json:"assign_time"`
 }
 
 func (database *Database) SaveTask(task *Task, project int64, hash64 int64) error {
@@ -53,7 +52,7 @@ func (database *Database) GetTask(worker *Worker) *Task {
 
 	row := db.QueryRow(`
 	UPDATE task
-	SET assignee=$1
+	SET assignee=$1, assign_time=extract(epoch from now() at time zone 'utc')
 	WHERE id IN
 	(
 		SELECT task.id
@@ -71,7 +70,7 @@ func (database *Database) GetTask(worker *Worker) *Task {
 
 	err := row.Scan(&id)
 	if err != nil {
-		logrus.WithFields(logrus.Fields{
+		logrus.WithError(err).WithFields(logrus.Fields{
 			"worker": worker,
 		}).Trace("No task available")
 		return nil
@@ -104,7 +103,7 @@ func getTaskById(id int64, db *sql.DB) *Task {
 	return task
 }
 
-func (database Database) ReleaseTask(id int64, workerId *uuid.UUID, success bool) bool {
+func (database Database) ReleaseTask(id int64, workerId int64, success bool) bool {
 
 	db := database.getDB()
 
diff --git a/storage/worker.go b/storage/worker.go
index 155f551..f089297 100644
--- a/storage/worker.go
+++ b/storage/worker.go
@@ -4,7 +4,6 @@ import (
 	"database/sql"
 	"errors"
 	"github.com/Sirupsen/logrus"
-	"github.com/google/uuid"
 )
 
 type Identity struct {
@@ -13,7 +12,7 @@ type Identity struct {
 }
 
 type Worker struct {
-	Id       uuid.UUID `json:"id"`
+	Id       int64     `json:"id"`
 	Created  int64     `json:"created"`
 	Identity *Identity `json:"identity"`
 	Alias    string    `json:"alias,omitempty"`
@@ -26,17 +25,18 @@ func (database *Database) SaveWorker(worker *Worker) {
 
 	identityId := getOrCreateIdentity(worker.Identity, db)
 
-	res, err := db.Exec("INSERT INTO worker (id, created, identity, secret, alias) VALUES ($1,$2,$3,$4,$5)",
-		worker.Id, worker.Created, identityId, worker.Secret, worker.Alias)
+	row := db.QueryRow("INSERT INTO worker (created, identity, secret, alias) VALUES ($1,$2,$3,$4) RETURNING id",
+		worker.Created, identityId, worker.Secret, worker.Alias)
+
+	err := row.Scan(&worker.Id)
 	handleErr(err)
 
-	var rowsAffected, _ = res.RowsAffected()
 	logrus.WithFields(logrus.Fields{
-		"rowsAffected": rowsAffected,
+		"newId": worker.Id,
 	}).Trace("Database.saveWorker INSERT worker")
 }
 
-func (database *Database) GetWorker(id uuid.UUID) *Worker {
+func (database *Database) GetWorker(id int64) *Worker {
 
 	db := database.getDB()
 
@@ -104,7 +104,7 @@ func getOrCreateIdentity(identity *Identity, db *sql.DB) int64 {
 	return rowId
 }
 
-func (database *Database) GrantAccess(workerId *uuid.UUID, projectId int64) bool {
+func (database *Database) GrantAccess(workerId int64, projectId int64) bool {
 
 	db := database.getDB()
 	res, err := db.Exec(`INSERT INTO worker_has_access_to_project (worker, project) VALUES ($1,$2)
@@ -129,7 +129,7 @@ func (database *Database) GrantAccess(workerId *uuid.UUID, projectId int64) bool
 	return rowsAffected == 1
 }
 
-func (database *Database) RemoveAccess(workerId *uuid.UUID, projectId int64) bool {
+func (database *Database) RemoveAccess(workerId int64, projectId int64) bool {
 
 	db := database.getDB()
 	res, err := db.Exec(`DELETE FROM worker_has_access_to_project WHERE worker=$1 AND project=$2`,
diff --git a/test/api_task_test.go b/test/api_task_test.go
index 14e3361..309f40a 100644
--- a/test/api_task_test.go
+++ b/test/api_task_test.go
@@ -3,7 +3,6 @@ package test
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/google/uuid"
 	"io/ioutil"
 	"src/task_tracker/api"
 	"src/task_tracker/storage"
@@ -66,9 +65,8 @@ func TestGetTaskInvalidWid(t *testing.T) {
 
 func TestGetTaskInvalidWorker(t *testing.T) {
 
-	id := uuid.New()
 	resp := getTask(&storage.Worker{
-		Id: id,
+		Id: -1,
 	})
 
 	if resp.Ok != false {
@@ -82,9 +80,8 @@ func TestGetTaskInvalidWorker(t *testing.T) {
 
 func TestGetTaskFromProjectInvalidWorker(t *testing.T) {
 
-	id := uuid.New()
 	resp := getTaskFromProject(1, &storage.Worker{
-		Id: id,
+		Id: 99999999,
 	})
 
 	if resp.Ok != false {
@@ -154,7 +151,7 @@ func TestCreateGetTask(t *testing.T) {
 		Priority:   9999,
 	}, worker)
 
-	taskResp := getTaskFromProject(resp.Id, genWid())
+	taskResp := getTaskFromProject(resp.Id, worker)
 
 	if taskResp.Ok != true {
 		t.Error()
@@ -314,8 +311,8 @@ func TestTaskNoAccess(t *testing.T) {
 		t.Error()
 	}
 
-	grantAccess(&worker.Id, pid)
-	removeAccess(&worker.Id, pid)
+	grantAccess(worker.Id, pid)
+	removeAccess(worker.Id, pid)
 
 	tResp := getTaskFromProject(pid, worker)
 
@@ -356,7 +353,7 @@ func TestTaskHasAccess(t *testing.T) {
 		t.Error()
 	}
 
-	grantAccess(&worker.Id, pid)
+	grantAccess(worker.Id, pid)
 
 	tResp := getTaskFromProject(pid, worker)
 
diff --git a/test/api_worker_test.go b/test/api_worker_test.go
index 9d1f2b4..781eea0 100644
--- a/test/api_worker_test.go
+++ b/test/api_worker_test.go
@@ -3,7 +3,6 @@ package test
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/google/uuid"
 	"io/ioutil"
 	"net/http"
 	"src/task_tracker/api"
@@ -25,7 +24,7 @@ func TestCreateGetWorker(t *testing.T) {
 		t.Error()
 	}
 
-	getResp, r := getWorker(resp.Worker.Id.String())
+	getResp, r := getWorker(resp.Worker.Id)
 
 	if r.StatusCode != 200 {
 		t.Error()
@@ -47,7 +46,7 @@ func TestCreateGetWorker(t *testing.T) {
 
 func TestGetWorkerNotFound(t *testing.T) {
 
-	resp, r := getWorker("8bfc0ccd-d5ce-4dc5-a235-3a7ae760d9c6")
+	resp, r := getWorker(99999999)
 
 	if r.StatusCode != 404 {
 		t.Error()
@@ -59,7 +58,7 @@ func TestGetWorkerNotFound(t *testing.T) {
 
 func TestGetWorkerInvalid(t *testing.T) {
 
-	resp, r := getWorker("invalid-uuid")
+	resp, r := getWorker(-1)
 
 	if r.StatusCode != 400 {
 		t.Error()
@@ -76,7 +75,7 @@ func TestGrantAccessFailedProjectConstraint(t *testing.T) {
 
 	wid := genWid()
 
-	resp := grantAccess(&wid.Id, 38274593)
+	resp := grantAccess(wid.Id, 38274593)
 
 	if resp.Ok != false {
 		t.Error()
@@ -90,7 +89,7 @@ func TestRemoveAccessFailedProjectConstraint(t *testing.T) {
 
 	worker := genWid()
 
-	resp := removeAccess(&worker.Id, 38274593)
+	resp := removeAccess(worker.Id, 38274593)
 
 	if resp.Ok != false {
 		t.Error()
@@ -112,7 +111,7 @@ func TestRemoveAccessFailedWorkerConstraint(t *testing.T) {
 		Public:   true,
 	}).Id
 
-	resp := removeAccess(&uuid.Nil, pid)
+	resp := removeAccess(0, pid)
 
 	if resp.Ok != false {
 		t.Error()
@@ -134,7 +133,7 @@ func TestGrantAccessFailedWorkerConstraint(t *testing.T) {
 		Public:   true,
 	}).Id
 
-	resp := removeAccess(&uuid.Nil, pid)
+	resp := removeAccess(0, pid)
 
 	if resp.Ok != false {
 		t.Error()
@@ -156,7 +155,7 @@ func TestUpdateAliasValid(t *testing.T) {
 		t.Error()
 	}
 
-	w, _ := getWorker(wid.Id.String())
+	w, _ := getWorker(wid.Id)
 
 	if w.Worker.Alias != "new alias" {
 		t.Error()
@@ -190,9 +189,9 @@ func createWorker(req api.CreateWorkerRequest) (*api.CreateWorkerResponse, *http
 	return resp, r
 }
 
-func getWorker(id string) (*api.GetWorkerResponse, *http.Response) {
+func getWorker(id int64) (*api.GetWorkerResponse, *http.Response) {
 
-	r := Get(fmt.Sprintf("/worker/get/%s", id), nil)
+	r := Get(fmt.Sprintf("/worker/get/%d", id), nil)
 
 	var resp *api.GetWorkerResponse
 	data, _ := ioutil.ReadAll(r.Body)
@@ -208,7 +207,7 @@ func genWid() *storage.Worker {
 	return resp.Worker
 }
 
-func grantAccess(wid *uuid.UUID, project int64) *api.WorkerAccessResponse {
+func grantAccess(wid int64, project int64) *api.WorkerAccessResponse {
 
 	r := Post("/access/grant", api.WorkerAccessRequest{
 		WorkerId:  wid,
@@ -223,7 +222,7 @@ func grantAccess(wid *uuid.UUID, project int64) *api.WorkerAccessResponse {
 	return resp
 }
 
-func removeAccess(wid *uuid.UUID, project int64) *api.WorkerAccessResponse {
+func removeAccess(wid int64, project int64) *api.WorkerAccessResponse {
 
 	r := Post("/access/remove", api.WorkerAccessRequest{
 		WorkerId:  wid,
diff --git a/test/common.go b/test/common.go
index d3f5f5e..bd26d30 100644
--- a/test/common.go
+++ b/test/common.go
@@ -12,6 +12,7 @@ import (
 	"net/http"
 	"src/task_tracker/config"
 	"src/task_tracker/storage"
+	"strconv"
 )
 
 func Post(path string, x interface{}, worker *storage.Worker) *http.Response {
@@ -27,7 +28,7 @@ func Post(path string, x interface{}, worker *storage.Worker) *http.Response {
 		mac.Write(body)
 		sig := hex.EncodeToString(mac.Sum(nil))
 
-		req.Header.Add("X-Worker-Id", worker.Id.String())
+		req.Header.Add("X-Worker-Id", strconv.FormatInt(worker.Id, 10))
 		req.Header.Add("X-Signature", sig)
 	}
 
@@ -51,7 +52,8 @@ func Get(path string, worker *storage.Worker) *http.Response {
 		mac.Write([]byte(path))
 		sig := hex.EncodeToString(mac.Sum(nil))
 
-		req.Header.Add("X-Worker-Id", worker.Id.String())
+		fmt.Println(strconv.FormatInt(worker.Id, 10))
+		req.Header.Add("X-Worker-Id", strconv.FormatInt(worker.Id, 10))
 		req.Header.Add("X-Signature", sig)
 	}
 
diff --git a/test/schema.sql b/test/schema.sql
index d108236..8770170 100755
--- a/test/schema.sql
+++ b/test/schema.sql
@@ -25,7 +25,7 @@ CREATE TABLE worker_identity
 
 CREATE TABLE worker
 (
-  id       TEXT PRIMARY KEY,
+  id       SERIAL PRIMARY KEY,
   alias    TEXT,
   created  INTEGER,
   identity INTEGER REFERENCES worker_identity (id),
@@ -46,7 +46,7 @@ CREATE TABLE project
 
 CREATE TABLE worker_has_access_to_project
 (
-  worker  TEXT REFERENCES worker (id),
+  worker  INTEGER REFERENCES worker (id),
   project INTEGER REFERENCES project (id),
   primary key (worker, project)
 );
@@ -56,14 +56,14 @@ CREATE TABLE task
   id              SERIAL PRIMARY KEY,
   priority        INTEGER DEFAULT 0,
   project         INTEGER REFERENCES project (id),
-  assignee        TEXT REFERENCES worker (id),
+  assignee        INTEGER REFERENCES worker (id),
   retries         INTEGER DEFAULT 0,
   max_retries     INTEGER,
   status          Status  DEFAULT 'new',
   recipe          TEXT,
   max_assign_time INTEGER DEFAULT 0,
   assign_time     INTEGER DEFAULT 0,
-  hash64          BIGINT UNIQUE
+  hash64          BIGINT  DEFAULT NULL UNIQUE
 );
 
 CREATE TABLE log_entry